Hydrogen technologies are our greatest hope for the decarbonising industry. If scientists could only find a scalable, cost-effective method of extracting hydrogen (H2) from seawater, then many of our power needs would be solved. But today’s electrolysis systems are not capable of generating H2 from saline water and de-ionization techniques are so energy-intensive that seawater methods have largely been disregarded.
However, not by the Leibniz Institute for New Materials in Saarland: This month, electrochemist Professor Volker Presser and his doctoral student Yuan Zhang made a giant leap towards solving the desalination question using a simple fuel cell. Presser explains in a : "Yuan Zhang had a revolutionary idea: we simply use the fuel cell itself to desalinate the seawater and then obtain freshwater, which can then be used in the fuel cell to produce hydrogen."
The chemistry is so straightforward that the experiment could be conducted in a school, but no one had thought of it before: The salinated water which is rich in common salt (NaCl) is introduced into the desalination fuel cell where the salt (NaCl) is forced to dissolve its bond with the water by the addition of H2 and O2 at the anode and cathode. The byproducts are hydrochloric acid (HCl) and sodium hydroxide (NaOH) plus electricity and freshwater, which can be used in a second cycle for producing hydrogen via electrolysis, or even for drinking.
"So we can now build a module from each fuel cell that not only generates electricity, but also produces drinking water quite incidentally. This can then also be used for hydrogen production. You just need hydrogen for that, but you can produce it 'green' via electrolysis with 'power to gas'," says Presser in the forementioned . The desalinating system could be coupled with PEM electrolysers (for producing H2 from wind or solar power) to produce the gas on an industrial scale in a circular process.